Earth's energy balance

The equilibrium between the radiant energy flux the Earth receives and the flux it returns to space. On a global average and over a sufficiently long period, the balance must be zero, which guarantees the planet's habitability conditions. The existence of this equilibrium between incoming and outgoing energy implies that the solar radiation (short-wave) absorbed by the Earth must equal the sum of the fraction of it that is directly reflected, plus the terrestrial radiation (long-wave infrared radiation) emitted by our planet. In round numbers, if 100 units of energy reach the top of the atmosphere (equivalent to the 342 W/m2 of incoming solar flux), 50 units are absorbed by the Earth's surface, 20 by the aforementioned atmosphere, and the remaining 30 are returned to space, which constitutes the planetary albedo. Current climate change is unbalancing the scales between what comes in and what goes out, since, as the concentration of greenhouse gases in the atmosphere increases, the atmospheric medium is absorbing more terrestrial infrared radiation, letting a smaller fraction escape into space. The consequence of this is the observed global warming.